Basic Animation Practice

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Animation Practice',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  AnimationController animationController;

  @override
  void initState() {
    animationController = AnimationController(duration: Duration(milliseconds: 1000), vsync: this);
    animationController.addListener(() {
      setState(() {
        print(animationController.value);
      });
    });
    super.initState();
  }

  @override
  void dispose() {
    animationController.dispose();
    super.dispose();
  }

  Widget buildFadeTransitionWidget({AnimationController controller, Widget widget}) {
    return AnimatedBuilder(
        animation: controller,
        child: widget,
        builder: (context, child) {
          return FadeTransition(opacity: Tween<double>(begin: 0, end: 1).animate(CurvedAnimation(parent: controller, curve: Curves.decelerate)), child: child);
        });
  }

  Widget buildScaleTransitionWidget({AnimationController controller, Widget widget}) {
    return AnimatedBuilder(
        animation: controller,
        child: widget,
        builder: (context, child) {
          return ScaleTransition(scale: Tween<double>(begin: 0, end: 1).animate(controller), child: child);
        });
  }

  Widget buildRotateTransitionWidget({AnimationController controller, Widget widget}) {
    return AnimatedBuilder(
        animation: controller,
        child: widget,
        builder: (context, child) {
          return RotationTransition(turns: Tween<double>(begin: 0, end: 0.5).animate(controller), child: child);
        });
  }

  Widget buildSizeTransitionWidget({AnimationController controller, Widget widget}) {
    return AnimatedBuilder(
        animation: controller,
        child: widget,
        builder: (context, child) {
          return SizeTransition(axis: Axis.horizontal, axisAlignment: 2, sizeFactor: Tween<double>(begin: 0, end: 1).animate(controller), child: child);
        });
  }

  Widget buildMultiTransitionWidget({AnimationController controller, Widget widget}) {
    return buildScaleTransitionWidget(
        controller: controller,
        widget: buildFadeTransitionWidget(
            controller: controller, widget: buildRotateTransitionWidget(controller: controller, widget: buildSizeTransitionWidget(controller: controller, widget: widget))));
  }

//
  @override
  Widget build(BuildContext context) {

    var tween = Tween<double>(begin: 0, end: 250).animate(animationController);
    return Scaffold(
      appBar: AppBar(
        title: Text("Animation"),
      ),
      body: Center(
          child:
         Container(
          width: tween.value / 2,
          height: tween.value,
          color: Colors.pink[400],
      )),
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.play_arrow),
        onPressed: () {
          if (animationController.isCompleted) {
            animationController.reverse();
          } else {
            animationController.forward();
          }
        },
      ),
    );
  }
}